docs: def usage():
      """
      Return the usage for the help command.
      """
      l_bracket = clr.stringc("[", "dark gray")
      r_bracket = clr.stringc("]", "dark gray")
      pipe = clr.stringc("|", "dark gray")
  
      app_name = clr.stringc("%prog", "bright blue")
      commands = clr.stringc("{0}".format(pipe).join(c.VALID_ACTIONS), "normal")
      help = clr.stringc("--help", "green")
      options = clr.stringc("options", "yellow")
  
      guide = "\n\n"
      for action in c.VALID_ACTIONS:
          guide += command_name(app_name, action,
                                c.MESSAGES["help_" + action])
  
      # remove the last line break
      guide = guide[:-1]
  
      return "{0} {1}{2}{3} {1}{4}{3} {1}{5}{3}\n{6}".format(app_name,
                                                             l_bracket,
                                                             commands,
                                                             r_bracket,
                                                             help,
                                                             options,
                                                             guide)